| Project/Area Number |
62570087
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General pharmacology
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TSURU Hiromichi Hiroshima University, Associate Professor, 医学部, 助教授 (80022820)
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| Co-Investigator(Kenkyū-buntansha) |
NEGITA Sumiko Hiroshima University, Instruction Clerk, 医学部, 教務員 (60136059)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Vascular sympathetic innervation / Decentralization / Denervation supersensitivity / Rabbit ear artery / Neurotransmitter release / ラジオエンザイム法 / 除神経後感受性増大 / 上頸神経節 / 神経伝達物質の遊離 / 薬物感受性増大 / キャノンの除神経の法則 |
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| Research Abstract |
1. Our previous studies have suggested that the prejunctional supersensitivity to transmural nerve stimulation (TNS) develops slowly and later than the postjunctional one to exogenous norepinephrine (NE) and potassium (Tsuru ＆ Uematsu, Japan. J. Pharmacol. 40: 273-282, 1986). This suggestion was pursued in the present study.
2. Under anesthesia, unilateral preganglionic fiber to the superior cervical ganglion (SCG) was excised and the contralateral side was left intact as the control. Decentralized and control arteries were isolated 1, 2, 4 and 8 weeks after decentralization operation.
3. Each arterial preparation was incubated with ^3H-NE 10^- M for 1 hr at 37゜c. Changes in intraluminal pressure was monitored and the perfusate was collected every 2 min by a fraction collector. Increase in ^3H-NE overflow from perfused and superfused artery by TNS was measured by a liquid scintillation counter. ^3H-NE overflow was remarkably increased at low frequenies in the artery of 8-weeks decentrali
… More
zation as compared with the contralateral control artery, while there was no significant change in the relatively short term decentralization.
4. ^3H-Norepinephrine uptake experiment was made after incubation with ^3H-NE 10^<-8> M for 1 hr at 37゜c in the absence and in the presence of cocaine 10^<-4> M. There was no significant difference in ^3H-NE uptake between the arteries of 8-weeks decentralization and control.
5. Catecholamines in the artery and SCG were assayed by the modified radioenzymatic thin layer chromatographic method. There was no significant difference in the content of dopamine, NE and epinephrine between the both arteries and SCG of 8-weeks decentralization and control, whereas catecholamine content in the denervated artery was remarkably decreased.
6. The present study confirms our previous suggestion that the increment in neurotransmitter release is responsible for supersensitivity of the chronically decentralized rabbit ear artery to TNS, and suggests that change in stimulus-secretion coupling may be involved although the mechanism remains to be resolved. Less
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